Abatacept in rheumatoid arthritis-associated interstitial lung disease: short-term outcomes and predictors of progression

Introduction: Interstitial lung disease in rheumatoid arthritis (RA-ILD) is an extra-articular involvement that impairs the prognosis and for which there is still no well-coded treatment. The aim of this study was to evaluate abatacept (ABA) effectiveness and safety in patients with RA-ILD. Methods: RA-ILD patients who started ABA treatment were consecutively enrolled. Chest high-resolution computed tomography (HRCT), clinical, laboratory and respiratory function variables were collected at baseline and after 18 months of ABA treatment. HRCT abnormalities were evaluated using a computer-aided method (CaM). ABA response was established based on the change in the percentage of fibrosis evaluated at HRCT-CaM, dividing patients into "worsened" (progression ≥ 15%), "improved" (reduction ≥ 15%), and "stable" (changes within the 15% range). The multivariate regression model was used to assess the associations between RA characteristics and ABA response. Results: Forty-four patients (81% women, mean age 59.1 ± 8.0, mean disease duration of 7.5 ± 3.1 years) were studied. Five patients (11.4%) showed RA-ILD progression, 32 patients (72.6%) were considered stable, and 7 patients (16.0%) showed an RA-ILD improvement. The proportion of current smokers was significantly different between "worsened" patients, respect to those defined as "improved/stable" (p = 0.01). Current smoking habit (p = 0.005) and concomitant methotrexate treatment (p = 0.0078) were the two variables related to RA-ILD progression in multivariate regression analysis. Conclusion: Treatment with ABA is associated with a RA-ILD stability or improvement in the 88.6% of patients. Current smoking habit and concomitant treatment with methotrexate are the modifiable factors associated with RA-ILD worsening. Key Points • Abatacept plays a favourable role in the control of RA-ILD, with a significant worsening in only 11.4% of patients during a 18-month follow-up period. • The predictive variables related to RA-ILD progression during abatacept therapy are the concomitant treatment with methotrexate and current smoking habit